Preheat oven to 350 degrees F. Spray bottom only of 9 x 5 x 3 inch loaf pan with nonstick cooking spray. Beat butter in large bowl with an electric mixer set at medium speed until light and fluffy. Add granulated sugar and brown sugar; beat well. Add egg, egg whites and vanilla; beat until well blended. Add mashed banana, and beat on high speed 30 seconds.
Combine flour, baking soda, salt and baking powder in medium bowl. Add flour mixture to butter mixture alternately with cream, ending with flour mixture. Add nuts to batter; mix well.
Pour batter evenly into prepared loaf pan. Bake until browned and toothpick inserted near center comes out clean, about 1 hour and 15 minutes. Cool bread in pan on wire rack 10 minutes. Removed bread from pan; cool completely on wire rack. Slice and serve with butter and jam.